I am happy no one got hurt!

First topic message reminder :

I shoot my Ruger MkII frame with a Volquartsen LLV-6 barrel. It is very accurate. To keep me on target I use a Volquartsen
muzzle weight and Volquartsen compensator. I know, the 22 has very little recoil as it is, however it has noticeably less 
muzzle rise with the combination of weight and compensator. 

Before a match, I shoot 5 rounds to dirty my barrel and yesterday was no different. I took 4 shots and looked at my target
and lo and behold not a single round on the paper...What the heck was going on?  I took shot number 5 and my muzzle 
break/compensator BLEW off the gun, hit the ceiling and landed at my feet.  See picture below.
https://i.imgur.com/ggn1p8O.jpg
https://i.imgur.com/Zt7dSsL.jpg

Here is a picture of how the muzzle break attaches. While this is a different break, it is a multiport vs uniport which
came apart. 
https://i.imgur.com/j2D5NRR.jpg

The compensator was secured as tightly as possible and part was still on the end of the barrel and the other part on the 
floor. Upon examination there was a bulge in the front. I have no idea what happened. There was, obviously a muzzle 
strike causing the bulge, but all 5 rounds?  I doubt a double charged 22LR cartridge would do that, or would it? The 
strikes must have started from shot one because there was nothing on target. I did shoot this same gun 2 days earlier
and there were no issues and accuracy was right on par...what could have happened in those 2 days is beyond me.

The ammo I shoot is good quality ammo, GECO semi-auto. I have been shooting it for years and never an issue.
I contacted Volquartsen and they said that this has happened in the past, all though not too often. They are sending 
me another break. I am now a bit hesitant to use the break on this barrel. 

$64,000.00 Question---what do you all think happened.

Are there three locating pins on your barrel that go in those three holes on the rear face?  If so, do you also need to use the nut to remove the brake?  

If that is the case, and removal is stiff, you can bend the web between the brake and its “barrel collar” during a stiff removal.  If it goes on stiff it will come off stiff.  So I’d only remove it once a year at most.

no holes in the barrel...those pins retain the knurled nut in the break. The nut spins b/c the pins ride in a circular groove. The break does not come apart.